1. Field of the Invention
The invention relates to pattern detection techniques in general, and in particular, to its application to communications technology.
2. Prior Art
Processing systems for monitoring a communications network, such as Local Area Networks (LAN), and awakening a processor upon receiving a predetermined command or pulse from the network is well known in the prior art. U.S. Pat. No. 5,404,544 is an example of such processing systems. In the patent, the link pulse described in the 802.3/ethernet standard is used by a link connecting module to manage electrical power consumed by the link connecting module and the device that the link connecting module connects to the link. The patent describes a specialized method for power management on LAN and appears not suitable for general usage.
U.S. Pat. No. 5,396,636 describes a power management method in which a data transmission link transmits Power On frame when power is to be restored to a particular host on the link. Prior to receiving the Power ON frame, the host is maintained in an off-power state with a small amount of power being provided to selected components in the module that connects the host to the link. Upon receiving the Power On frame, full power is restored to the host. This method is a specialized situation in which only one fixed command can be used to wake-up the host.
The general drawback with the above patents is that a specialized wake-up frame must be transmitted from the “waker” to the “wakee”.
The Device Class Power Management Reference Specification, jointly authored by Microsoft® and Advanced Micro Devices®, Inc. refer to a more general approach in which patterns and byte masks are used to effectuate wake-up of a station. However, the specification does not provide an implementation.